Any reason to use a rack-mountable server if I lack a rack to mount it on?
I'm somewhat new to server hardware, and was wondering if there was any reason to purchase a 19-inch-rack-mountable server as opposed to a standalone (tower) system, or any difference between the two other than form factor.
We're running a small operation, so we will probably never have enough equipment to justify a full rack.
Solution 1:
Form factor is the main difference, and it doesn't take too many servers (5 or 6) before you really want rackmounted gear. You can get telco 'relay' racks for ~$100 or so, and if you've got rackmounted servers then all 6 or 10 of them (depending on height) will fit in one rack, taking up about 3sqft of space... whereas if you try and put 6 full towers in a room, you're going to need a lot more space than that.
Other than space, no, there's no good reason to do so - in fact, rack servers can be a poor fit for an office environment because without a rack to put them in they're kind of awkwardly shaped, and their cooling fans aren't aimed toward low noise at ALL so can best be described as 'jet engine-like' upon startup.
Solution 2:
If you don't anticipate a rack in your near future, rack mountable servers will just be a waste of money. They're designed with a rack environment in mind (form factor, obviously, but also the cooling and port/button/drive access) and cost more than an equivalent tower server.
Tower servers are generally easier to place and physically work on outside of a rack. The hardware in similarly specced servers will be equivalent, though it can sometimes be harder to find really high-end stuff in a tower form factor. If your operation doesn't need a rack, they probably don't need those super higher-end features.
Solution 3:
Why not look at a HP ML-series server, they come as towers but are easily converted to be rack-mounted cheaply if required. In particular the new ML350/370 G6's (1/2 Nehalem Xeons, upto 144GB mem, 24 disks) are nice-enough machines for the money (http://h10010.www1.hp.com/wwpc/us/en/en/WF04a/15351-15351-241434-241646-241477.html)